Allow Mojo structs as map keys

mojo/public/cpp/bindings/array.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_ARRAY_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_ARRAY_H_
 
 #include <stddef.h>
 #include <string.h>
 #include <algorithm>
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
 #include "mojo/public/cpp/bindings/lib/array_internal.h"
 #include "mojo/public/cpp/bindings/lib/bindings_internal.h"
 #include "mojo/public/cpp/bindings/lib/clone_equals_util.h"
+#include "mojo/public/cpp/bindings/lib/hash_util.h"
 #include "mojo/public/cpp/bindings/lib/template_util.h"
 #include "mojo/public/cpp/bindings/type_converter.h"
 
 namespace mojo {
 
 // Represents a moveable array with contents of type |T|. The array can be null,
 // meaning that no value has been assigned to it. Null is distinct from empty.
 template <typename T>
 class Array {
  public:
@@ skipping 145 matching lines @@
 
   // Indicates whether the contents of this array are equal to |other|. A null
   // array is only equal to another null array. If the element type defines an
   // Equals() method, it will be used; otherwise == operator will be used.
   bool Equals(const Array& other) const {
     if (is_null() != other.is_null())
       return false;
     return internal::Equals(vec_, other.vec_);
   }
 
+  size_t Hash(size_t seed) const {
+    return is_null() ? seed : internal::Hash(seed, vec_);
+  }
+
  private:
   typedef std::vector<T> Array::*Testable;
 
  public:
   operator Testable() const { return is_null_ ? 0 : &Array::vec_; }
 
  private:
   // Forbid the == and != operators explicitly, otherwise Array will be
   // converted to Testable to do == or != comparison.
   template <typename U>
@@ skipping 75 matching lines @@
   if (a.is_null())
     return !b.is_null();
   if (b.is_null())
     return false;
   return a.storage() < b.storage();
 }
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_ARRAY_H_